Department of Immunobiology, Faculty of Life Sciences and Medicine, King’s College London, London SE19RT, UK.Department of Diabetes and Endocrinology, Guy’s and St Thomas’ Hospital National Health Service (NHS) Foundation Trust, London SE19RT, UK.

Department of Immunobiology, Faculty of Life Sciences and Medicine, King’s College London, London SE19RT, UK.National Institute of Health Research Biomedical Research Centre at Guy’s and St Thomas’ Hospital and King’s College London, London SE19RT, UK.

Department of Immunobiology, Faculty of Life Sciences and Medicine, King’s College London, London SE19RT, UK.National Institute of Health Research Biomedical Research Centre at Guy’s and St Thomas’ Hospital and King’s College London, London SE19RT, UK.King’s Health Partners Institute of Diabetes, Endocrinology and Obesity, London SE19RT, UK.

Fig. 4.Analysis of T cell responses according to treatment and in peptide-treated C-peptide responders and nonresponders.

(A) Cumulative mean CD4 T cell IL-10 and IFN-γ responses to proinsulin stimulation measured over the duration of the 6-month treatment period shown according to treatment group. (B) Mean CD4 T cell IL-10 and (C) IFN-γ responses to proinsulin stimulation measured at each month during therapy in peptide-treated subjects divided according to C-peptide responder status. Bars and symbols represent mean stimulation index (SI) at each time point, and error bars are the 95% confidence intervals (CI). For analysis over the treatment period, longitudinal measurements of the SI were transformed using the natural logarithm (“Ln”) and were analyzed with linear models having visit and treatment as main factors and a repeated-measures error structure. Estimates of the mean SI across visits were computed using model-based estimates (least-squares means). (D) Change in FOXP3 expression levels [mean fluorescence intensity (MFI)] on all Treg subsets (CD4+CD25hiFOXP3+), (E) on memory (CD45RA−) adaptive Tregs, and (F) on memory CD39+ Tregs in peptide-treated subjects divided according to C-peptide responder status. (G) Change in Helios expression by Tregs in the same period and same groups. (H) Mean percentage levels of antigen-experienced (CD57+) CD8 T cells stained with peptide-HLA tetramers loaded with β cell peptides at baseline and at 6 months in peptide-treated C-peptide responders, compared with placebo and nonresponder subjects. Error bars show means and SEM. (B to H) C-peptide responders/nonresponders defined as having a post-baseline value that is 100% or more of the baseline value of C-peptide AUC during the treatment period. There were 9 peptide-treated C-peptide responders (6 of 9 subjects in the low-frequency and 3 of 7 in the high-frequency groups) and 10 nonresponders.

Proinsulin/C-peptide ratio measured at fasting and at 90 min during the MMTT in peptide-treated subjects who are C-peptide nonresponders (A and B) and responders (C and D). P values are for comparisons against the corresponding baseline. Error bars show means and SEM.